Universities play a well-established role in regional economic growth, one contribution to which is academic entrepreneurship, the establishment and support of faculty and graduate student spinoff companies based on university research. A vibrant literature examines the general contributions of universities within regional innovation ecosystems while another strain of literature examines individual intermediaries, such as technology licensing offices and incubators, in support of the university’s economic development mission. Little research exists, however, that conceptualizes the structure and function of an entrepreneurial university ecosystem. This paper seeks to address this gap in the literature by examining the composition, contributions, and evolution of social networks among faculty and graduate student entrepreneurs and the role of knowledge intermediaries therein. While our investigation supports an emerging literature that finds academic entrepreneurs are typically limited by their own homophilous social networks, we also find that spinoff success relies upon academic and non-academic contacts who connect faculty and students to other social networks important to spinoff success. We investigate how by creating a taxonomy of social network evolution among spinoffs; the results show that the contributions of universities depend on the existence and interrelationship of loosely coordinated, heterogeneous knowledge intermediaries guided by a strong collective ethos to encourage and support academic entrepreneurship.